236 Professor Edward B. Poultou on the 



apparatus lias been evolved by the a<rency of tliis 

 principle rather than by that of natural selection. 



Others may draw opposite conclusions from the same 

 observations, which I therefore set forth by themselves, 

 apart from general theoretical considei^ations. I believe 

 that the observations themselves are correct, and that the 

 uncertain points are stated with due caution. 



Pezotettix pedestris. 



August 29, 1895. — I watched a pair of Pe;:oleliix 

 2')€destris continuously for about an hour and a quarter, 

 viz , from about 2.30 p.m. to 3.45. The day was fine and 

 the sun powerful, and this had been the case for many 

 days previous to the 29th. 



When first observed, the male was seated on the back 

 of the female, the anterior legs being clasped round her 

 prothorax, but every now and then one of them was 

 passed round her head and sometimes even over the eye. 

 Twice the female was seen to raise her leg and sweep the 

 male's leg off her face. The male's second pair of legs 

 apparently clasped the posterior part of her first 

 abdominal segment, fitting in between the femora of 

 the female's third pair of legs and her body. The male's 

 third pair of legs were not used for maintaining his 

 position, but were held either horizontally or inclining 

 upwards postei-iorly, the tibias forming an acute angle 

 with the femora, and the tarsus being raised so as to form 

 an acute angle with the tibiaj. For nearly the whole of 

 the time of observation the male's third legs were jerked 

 lip and down alternately, the strokes not succeeding each 

 other very rapidly. No audible sound was produced. 

 No corresponding movement was seen on the part of the 

 female. 



In attempting to copulate, the male let himself down, 

 sometimes on one side and sometimes on the other, suffi- 

 ciently far to bring the extremity of the abdomen below 

 that of the female. The terminal segments of the male's 

 abdomen were then turned upwards and inwards towards 

 the external generative aperture of the female, with which 

 the everted male organs were brought into contact. No 

 movement of the corresponding female parts was seen, 

 but contractions of the whole abdomen occasionally took 



